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Fertilizer
Guide
This fertilizer guide provides information for cranberry
fertilization in Coos and Curry Counties where cranberries
are planted in irrigated beds of sandy loam soil. Uniform
irrigation is essential for optimum cranberry growth since
moist but not saturated soils are required.
The goal of cranberry fertilization, as for any high-value
crop, is to remove limitations to yield and quality by supplying
the crop with ample nutrition in advance of demand. Growers
should consider the fertilizer needs of each cranberry bed
rather than treating their entire acreage the same way.
Foliar fertilization of cranberries is practiced by growers
with little evidence supporting its benefits. Although
fertilizers may enter through leaves, there is little information about how this compares to standard practices.
Fertilizer need should be determined through soil and tissue
analyses in conjunction with weather records, crop yield and
fruit quality, and an assessment of pest problems. Production
costs, environmental stewardship, and governmental
regulation should also be considered. Fertilization should be
based on yield or quality response, experience, and economics.
Plants indicate low nutrient supply through reduced growth
and yield. Reduced nutrient supply below crop demand can
lead to visible nutrient deficiency symptoms. Routine
collection and analysis of soil and tissue samples are helpful
in detecting low nutrient concentration before visible
symptoms and yield reduction occur. An Extension publication, FG 74, Analytical Laboratories Serving Oregon,
provides information about laboratories that offer soil and
tissue testing services. It is available in local Extension
offices or can be ordered from OSU Agricultural Communications. See the For More Information section for ordering
instructions.
Soil and Tissue Sampling
Obtain soil samples during the dormant season after flood
management and before bud break. Sampling depth should
be 4 inches on new or young beds or 6 inches including
surface duff on mature, well established beds. Obtain 10 to
12 cores from the same area that tissue samples are taken.
Avoid poorly drained areas, high spots or other nonrepresentative areas. Sample problem areas separately. Routinely
test soil for pH, phosphorus (P), potassium (K), calcium
(Ca), magnesium (Mg), boron (B), and zinc (Zn).
OREGON STATG UNIVCRSITY
eXTENSION
SERVICE
FG 75
Reprinted July 1994
South Coastal Oregon
CRANBERRIES
In addition to soil testing, tissue analyses are used to help
assess fertilizer requirements during the following growing
season. A cranberry tissue sample is obtained by clipping
current season growth from just above the berries on fruit
bearing uprights. Twenty tips each from 10 locations
representative of the bed are needed. The total sample will
consist of 200 tips per bed. Do not wash the sample or
separate leaves and stems before submission of the tissue
sample to the laboratory. Collect tissue samples during midAugust to mid-September, prior to harvest.
Routinely analyze cranberry tissue for total nitrogen (N), P,
K, Ca, Mg, sulfur (S), B, Zn, copper (Cu), and manganese
(Mn). Many laboratories provide analyses for additional
micronutrients such as iron (Ft). These other analyses may
be helpful in problem or "troubleshooting" situations but are
difficult to interpret from routine sampling.
Using Soil and Tissue Tests
Cranberry tissue test values for N, P, K, and S are divided
into below normal, normal, and above normal categories.
Tissue concentrations for Ca, Mg, B, and Zn, are placed into
only two categories, sufficient and deficient. If a tissue
concentration is below normal or deficient, fertilization with
the appropriate nutrient is recommended. The categories are
based on nutrient ranges from other cranberry growing
areas, grower observations, Oregon cranberry tissue
analyses, and limited Oregon field trials.
Annual monitoring of soil and leaf tissue is suggested. In
addition, recording data on fertilizer applications, weather,
and yield would be helpful. Soil and tissue analyses won't
identify an exact amount of fertilizer to apply. However,
they are useful for evaluating nutrient sufficiency and
fertilizer applications. Soil and tissue tests are best used to
evaluate a program of several years duration rather than for
a single year. Therefore, record keeping is a vital component
of soil and tissue analyses interpretation.
Insufficient nutrition is only one cause of reduced yields.
Saturated or dry soils, high temperatures, frost, shading,
weed, insect or disease pressure or herbicide injury also
reduce yields. Fertilization will not compensate for these
problems. If adequate nutrition is present, fertilizing is an
unnecessary expense and potentially detrimental to the
environment.
Extension Service, Oregon State University, Corvaltis, O.E. Smith, director. This publication was produced and distributed in furtherance of the Acts of Congress of May Sand June 30. 1914. Extension work is a cooperative program
of Oregon State University, the U.S. Department of Agriculture, and Oregon counties. Oregon State University Extension Service offers educational programs, activities, and materials—without regard to race, color, national origin,
sex, age. or disability—as required by Title VI of the Civil Rights Act of 1964, Title IX of the Education Amendments
of 1972, and Section 504 of the Rehabilitation Act of 1973. Oregon State University Extension Service is an Equal
Opportunity Employer.
3276/
The standard fertilization schemes that follow involve a
series of applications that can be modified depending on soil
and plant analyses, vigor, and crop performance.
Fertilization of a perennial crop such as cranberries may not
affect tissue analysis levels for 1 to 2 years after application.
Nitrogen (N)
Bearing beds
Adequate tissue N levels are necessary to maintain growth,
crop production, and flower bud development for next year's
crop. Excess N leads to excessively vegetative growth, which
restricts flower bud formation and delays fruit maturity. Soil
testing for N is not a reliable indicator of perennial crop N
status. Leaf analysis alone does not indicate whether N
fertilization is required but can be used with an assessment of
plant growth and productivity to determine N status.
Nitrogen fertilization rates are based primarily on field
observation and to a lesser extent on plant analysis. Nitrogen
concentration should be interpreted with an assessment of
plant vigor. Normal growth for flowering uprights is 2 to 4
inches per year. Flowering upright growth less than 2 inches
is below normal. Conversely, flowering upright growth
greater than 4 inches is above normal.
Above normal N and high vigor indicate over fertilization of
N. Below normal N and low vigor indicate a need for more
N. Above normal N and low vigor suggest another growth
limiting factor such as poor drainage. Below normal N and
high vigor can occur in beds with little or no crop. Table 1
provides a guide to cranberry N tissue concentrations.
Table 1. Percent leaf N for mature beds in August-September.
Standards for McFarlin, Stevens, and Crowley cultivars
combined on a dry weight basis.
%LeafN
Under 0.90
0.90-1.25
Over 1.25
Status
Below Normal
Normal
Above Normal
Cranberries respond best to ammonium N. Usually, broadcast
applications of dry materials are spread more evenly than applications made through sprinkler systems. To avoid plant injury,
apply materials to dry vines, then rinse with irrigation water.
At fruit set and sizing time, growers should observe terminal
leaves on flowering uprights turn from a healthy green color
to a pale yellowish green. Growers should also notice
terminal leaf margins turn red and leaf bases and mid-ribs
remain green. These natural signals of stress indicate normal
nutrient flow from current season growth to developing fruit.
Recent research supports these observations.
For most beds, optimum timing of N for fruit set, berry size
and bud initiation appears to be from when berries are peasized until the last flower falls, a period of 3 to 4 weeks.
For established plantings of 'Crowley' and 'McFarlin', if the
bed is not over vegetative, apply 5 to 10 lb N/a at late hook/
early bloom stage. Nitrogen applied between popcorn and
early bloom often produces excessive growth, especially
during cloudy or rainy periods. Withhold further N until
berries are pea or marble size throughout the field, then apply
10 to 20 lb N/a. For 'Stevens', wait until pea sized berry
stage occurs before beginning N fertilization. Blossoms will
still be present in the field at this time. Earlier N fertilization
produces excessive vegetative growth.
Apply 10 to 20 lb N/a every 7 to 14 days until berry sizing
appears complete. An alternative is to apply 20 lb N/a twice at
2 week intervals during the same period. Rate of N will vary
depending upon crop potential and stress conditions such as
herbicide use, frost injury, and drainage. A final application
of 5 to 10 lb N/a may be applied in late July to early August
to maintain plant vigor and to further encourage bud development. Nitrogen fertilization after fruit is sized should be
reduced, since research has shown that little N is taken up in
cranberry plant tissues and fruit at that time. Use bee activity
during bloom to help determine N timing. Make final N
applications 1 to 3 weeks after bee activity stops.
Where vines are weak or stressed, however, a post-harvest
application of 5 lb N/a may be helpful. Heavy applications of
N late in the season encourage berry rot, delay ripening and
color development, and stimulate bud growth, increasing the
risk of winter injury.
New Beds
For new plantings (first year), apply 5 to 10 lb N/a when '^
inch of growth is observed. Then apply 10 lb N/a no more
than every other week until September or until appropriate
vigor and runner growth is achieved. New beds are fertilized
to encourage rapid soil coverage and root growth for early
establishment and to discourage weed competition.
Irrigate to maintain a moist but not wet soil environment. If
water puddles consistently, adjust sprinklers, reduce irrigation amounts, or improve drainage. Cranberries may die or
lose vigor if standing water is chronic. Establishment is
achieved when runners generate new uprights and terminal
buds. When sufficient uprights and buds have been formed,
apply N according to the scheme outlined for bearing beds.
Phosphorus (P)
In established beds, apply P at the white bud/popcorn stage
in late March or early April according to table 2. Where
vines are weak, a post-harvest application of 10 to 20 lb
P205/a may be helpful.
Efficient use of P fertilizer depends on fertilizer placement as
P is not mobile in soil. The fibrous root system of cranberry
develops in the top 1 to 3 inches of soil. Therefore, on new
plantings, apply xl2 to Vj of the P fertilizer before the final
sand layer if that sand layer is only 2 to 3 inches deep. Apply
the remaining P after scattering vines but before disking.
Phosphorus could also be applied just before vines are
scattered and disked. If vines have already been planted,
split the P applications in the first year, applying half as
growth starts and half at midseason.
Table 2. Cranberry phosphorus sufficiency and fertilizer recommendations based on soil and tissue tests.
If the Bray soil test
for P is (ppm)
0-15
15-30
Over 30
If cranberry
status is
If % Plant Pin
Aug-Sept is
Status
Under 0.10
0.10-0.25
Over 0.25
Below Normal
Normal
Above Normal
Broadcast this amount
0fP2O5(lb/a)
40-80
0-40
0
Below Normal
Normal
Above Normal
Calcium (Ca)
Sufficient Ca may be supplied by 0-45-0 (12 to 14 percent
Ca) fertilizer and bordeaux fungicide. Apply Ca as gypsum
(calcium sulfate) between white bud/popcorn and roughneck
stages according to table 5. Caution: excess soil calcium could
enhance unwanted legumes ability to invade cranberry beds.
Table 5. Cranberry calcium sufficiency and fertilizer
recommendations based on soil and tissue analysis.
* If the Ca soil
test is (meq/lOOg)
If % Plant Cain
Aug-Sept is
Apply this amount
of gypsum 0b/a)
Under 0.50
Under 0.60
100
Potassium (K)
Magnesium (Mg)
An adequate supply of K is needed for the high K requirement of young leaves and berries. Multiple applications of
K fertilizer are recommended to compensate for leaching in
sandy soils. If dry K fertilizers are applied, rinse material
from foliage with irrigation to prevent fertilizer bum.
Litde is known about Mg nutrition of cranberries, and,
according to Eck in The American Cranberry, no reports of
yield or growth increases to Mg applications have been
published. Eck also reports that blueberries grown on the
same soil as cranberries sometimes exhibit Mg deficiency
symptoms. The limited growth of cranberries compared to
blueberries may be one factor in the lower Mg requirement
of cranberries. In addition, the evergreen growth habit of
cranberries may allow Mg to be translocated from old to
new growth.
Table 3. Cranberry potassium sufficiency and fertilizer
recommendations based on soil and tissue analysis.
*If the soil test
for K is (ppm)
If % Plant Kin
Aug-Sept is
Status
0-50
50 -100
Over 100
Under 0.40
0.40 - 0.65
Over 0.65
Below Normal
Normal
Above Normal
If cranberry
status is
Below Normal
Nornial
Above Normal
Broadcast this amount
ofK2OQb/a)
60 - 100
0-60
0
When K is required, apply 25 percent of the total to be
applied at white bud/popcorn stage in late March or early
April, 25 percent at hook stage in May, 25 percent at midfruit set stage in late June - early July, and 25 percent at latefruit set stage in late July to early August. Where vines are
weak, a postharvest application of 10 to 20 lb K^O/a may be
helpful. Amounts to apply can be determined from table 3.
Though little information on cranberry Mg nutrition exists,
the choice of 0.15 percent tissue Mg from a late summer
sampling is supported by tissue analyses summaries and is
consistant throughout North American growing regions.
Analyses of Oregon cranberry tissue from 1974 to 1988
show most samples were between 0.17 and 0.24 percent Mg.
Only 2 percent of the samples were below 0.17 percent.
South coastal Oregon cranberries are routinely fertilized
with Mg. If Mg is deficient, a greater distribution of tissue
Mg concentration would be expected. Low tissue Mg can
be caused by Ca and K fertilization and reflected by high
tissue Ca and K concentration. In this situation, reduce Ca
and K applications. Apply Mg at white bud/popcorn stage
according to table 6:
Table 6. Cranberry magnesium sufficiency and fertilizer
recommendations based on soil and tissue analysis.
Sulfur (S)
Plant analysis is used for prediction of cranberry S needs.
Table 4. Cranberry sulfur sufficiency based on tissue
analysis.
If % Plant Sin
Aug-Sept is:
Status
Under 0.10
0.10-0.30
Over 0.30
Below Normal
Normal
Above Normal
Fertilizer materials used to supply the other nutrients
normally contain more than adequate S. Therefore separate
apphcations of S are not recommended.
pH
Cranberries grow best in south coastal Oregon between pH
4.5 and 5.5. Treatments to change pH status of cranberry
beds are usually not advised since native soils are in this pH
range.
♦IftheMg
soil test is
(meq/lOOg)
If % Plant Mg in
Aug-Sept is
Under 0.30
Under 0.15
Broadcast this amount
of Mg (lbs/a)
20
Boron (B)
Boron can be toxic to cranberries if applied in excess.
Apply B only when the need is indicated by soil or plant
analysis. An annual maintenance application is suggested
unless soil and plant analyses indicate above normal
amounts. Use a soluble form of B broadcast by sprayer or
sprinkler. Do not mix it with copper materials. Apply
between roughneck and early bloom.
Table 7. Cranberry boron sufficiency and fertilizer
recommendations based on soil and tissue analysis.
*IftheB
soil test is (ppm)
If Plant Bin
Aug-Sept is (ppm)
Under 0.50
Under 25
Apply this amount
of B (lb/a)
Zinc (Zn)
Soluble forms, such as zinc sulfate or chelate, can be applied
Table 8. Cranberry zinc sufficiency and fertilizer
recommendations based on soil and tissue analysis.
Dy sprayer or spnniaer. Apply only wnen neeaea oetween
roughneck and early bloom.
If the DTPA soil test
forZnis(ppm)
If Plant Zn in
Aug-Sept is (ppm)
Apply this amount
of Zn 0b/a)
Under 0.80
Under 15
lto2
GUIDE TO TIMING OF CRANBERRY FERTILIZATION IN BEARING BEDS
Nutrient
White Bud /
Popcorn
Nitrogen (N)
a
Phosphorus (P205)
0-80
Potassium (K^O)
0-25
Calcium (Ca)
x
Magnesium (Mg)
0-20
Roughneck
Late Hook/
Early Bloom
5-10
Mid-Fruit
Set
lb/a
10-20
Late Fruit
Set
Bud
Development
10-20
PostHarvest
0-5b
0-20b
0-25
0-25
0-25
0-20b
xd fas evpsum)
0 - lOO'
Boron (B)
x
0-1
x"
Zinc (Zn)
x
0-2
x"
a Apply 5 to 10 lb N/a if vines are weak. Excess growth can occur in warm and wet weather for beds with duff buildup. Avoid early N
treatments in second year beds if first year growth was abundant Also, avoid early N use on 'Stevens'.
b Post-harvest fertilization usually is not needed. However, apply immediately after harvest if the vines are weak.
c Apply 100 lb calcium sulfate/a (gypsum) if needed. Gypsum contains 19 to 23 percent calcium.
d Apply during the period marked between X's or according to the product label. Post-bloom applications are not recommended.
For More Information
Eck, P. 1971. Cranberry Growth and Composition as Influenced by
Nitrogen Treatment. HortScience6(l):38-39.
To order FG 74, Analytical Laboratories Serving Oregon, write
Publications Orders, Agricultural Communications, Oregon State
University, Administrative Services A422, Corvallis, OR 97331-2119.
There is no charge for this publication.
Eck, Paul. 1990. The American Cranberry. Rutgers University Press,
New Brunswick, NJ.
Birrenkott, B. A., C. A. Henson, and E. J. Stang. 1991. Carbohydrate
Levels and the Development of Fruit in Cranberry. J. Amer. Soc. Hort.
Sci. 116(2):174-178.
Caruso, F. L., A. L. Averill, I. E. Demoranville, R. M. Devlin and C. J.
DeMoranville. 1993. In: M. M. Averill (ed.) Cranberry 1993 Chart
Book, Management Guide for Massachusetts. A joint publication of
the Cranberry Experiment Station, MA Agricultural Experiment
Station, and Coop. Extension, East Wareham, MA.
Chaplin, M. H. and L. W. Martin. 1979. Seasonal Changes in Leaf
Element Content of Cranberry, Vaccinium Macrocarpon Ait.
Commun. in Soil Sci. and Plant Analysis, 10(6):895-902.
Eaton, G. W. 1971. Effect ofN, P, and K Fertilizer Applications on
Cranberry Leaf Nutrient Composition, Fruit Color and Yield in a
Mature Bog. J. Amer. Soc. Hort. Sci 96(4):430-433.
Galletta, G. J. D. G. Himelrick, (ed), and L. Chandler (illust). 1990.
Small Fruit Crop Management. Prentice Hall, Englewood Cliffs, NJ.
Roper, T. and S. Coombs. 1992. Nutrient Status of Wisconsin Cranberries. Cranberries: The National Cranberry Magazine, 15(2):11-15.
Roper, T. 1992. Cranberry Soil and Tissue Analysis: Diagnostic
Tools. The Wisconsin Cranberry IPM Newsletter. A joint publication
of the University of Wisconsin, Ocean Spray Cranberries, Inc., The
Wisconsin Cranberry Board, Inc., Cliffstar Corporation, and private
crop consulting services, Madison, WI. 6(7):l-2.
Torio, J. C. and P. Eck. 1969. Nitrogen, Phosphorus, Potassium and
Sulfur Nutrition of the Cranberry in Sand Culture. J. Amer. Soc. Hort.
Sci. 94(6):622-625.
Wood, J. H., L. Warner, and W. L. Powers. 1950. Preliminary Report,
Water and Nutrient Relations for Cranberries. Oregon State College
Extension Service, Experiment Station Soils Department. (Now
Oregon State University, Corvallis, OR).
Arthur Poole, Extension agent. Coos County; John Hart, Extension soil scientist; Tim Righetti, professor of horticulture; and
Bemadine Strik, Extension horticulture specialist; Oregon State University. Tissue and soil analyses are based on procedures used by
OSU. Soil Mg, Ca, and K are determined from an ammonium acetate extraction. Boron is extracted with hot water and Zn from a
DTPA extraction. N recommendations are based on tissue analysis groupings from Plant Analysis Laboratory data and field research.
Other recommendations are based on Extension experience and grower observation.